One of the major medical problems today is that associated with lack of control of blood pressure in humans; indeed hypertension is a leading cause of disease and death in the United States. It has been reported that over fifteen percent of the United States population has hypertension at present, controlled by intermittent oral therapy or emergency intravenous medication.
For control of blood pressure, accurate and dependable measurement of blood pressure is necessary to both determine the presence of a problem and for monitoring the pressure to assure alleviation or control of such a problem. For best results, the measurement of blood pressure should be continuous. At present, however, blood pressure measurement is normally an intermittent process due to the constraints imposed by the pressure transducers available for utilization, which include a pressure cuff outside the body, which cuff cannot be maintained for long period of time on a human, or by an implanted transducer.
Implanted pressure transducers have been suggested that might enable continuous measurement of blood pressure. But such transducers have not been satisfactory in achieving pressure measurement that can be continuously maintained for relatively long periods. With respect to the implantable type of pressure transducer, it has been shown to be usable only for periods of up to ninety days. Even if such transducers could be developed to the point of providing long-life, problems would accrue due to the necessity for such transducers to be in direct contact with blood.